harshmane:

I'd suggest first reindenting your program so the structure is clear (use perltidy or the indenting feature of a [no such wiki, comparison of text editors] such as vim, emacs, etc).

Next, for a program as small as this one, pretend you're the computer, and simply do the operations one by one. If you're moderately careful, you'll find the bugs pretty easily as you'll find your program telling you to do things at the wrong time. Just take a sheet of paper and write a small simple data set on it at the top. Use the bottom to keep track of the values of variables and the output file. Then, as you find the bugs, repair them.

While I find desk work like that a bit relaxing, you'll find that more complex programs require far too much work to do by hand. That's when using the perl debugger comes in handy. Learn how to use it, and it will help you become a better programmer.

But for this program, it would be instructive if you do it by hand so you can get a feel for how to read a program and find errors. As an example, for the program:

my $total=0;
for my $val (2 4 6 8) {
   $total += $val;
}
print $total;
[download]

My worksheet would look something like:

total: 0 2 6 12 20

val: 2 4 6 8

...roboticus

When your only tool is a hammer, all problems look like your thumb.

The three most important words in posting

Preview, Preview, Preview. Even though, in most cases, you can edit your node after it has been submitted, some sections of the site do not allow this, so be sure that everything is looking how you want others to see it before you finally hit Submit. (In your User Settings you can switch off the forced preview. But don't. Even the most experienced monks still preview before posting. Your humble author has previewed up to eight times on some posts, just to make sure it would look right.)

Hi, the code you posted does not compile, part of asking a question effectively, is to make sure your code compiles before posting.

while(<FH>){
...
[download]

This reads from a file until it reaches the end. Filehandles are iterators. Once you reach the end, the subsequent while(<FH>) loop will not be entered

@arr =$_;

This sets @arr to the value of $_; It doesn't add values to @arr, for that you need the push function

i m rewriting the current code here i m printing the give n part but i want it in between.

use warnings;
use strict;
 my $fg=0;
my $i=0;
open(FF ,"lib");
open (FF1,>lib1");

while(<FF>)
{
  my  $lin =$_;
  print FF1 $lin;
   if ($lin=~m/pattern to be patched for stat copying/)
  {   $fg=1;
   }
   if ($fg)
{  

   $lin=$_;

  my  @arr =$lin[$i];
     $i++;
 }
if($lin=~m/pattern where to stop copying & repeating/)
{ $fg=0;
}

}
  if ($fg==0)

{
  for (my $j=0;$j<$i;$j++)

{
   print FF1 @arr[$j];
}
}
[download]

i want to actuaaly print the given para in between here using these script i am print @ end of file.

Congratulations, you're getting closer :)

Your if logic is clear now, and correct, you're almost finished

But, your code once again does not compile, and has not been tidied, and you're still not push-ing onto the array

You attempt to compensate by using an index, but you're using it on the wrong variable

strict tells you about this

Global symbol "@lin" requires explicit package name

Global symbol "@arr" requires explicit package name

There is no @lin array, and @arr does not exist outside of the if block, where you assign to it, instead of pushing

You need to increase the scope of @arr, by declaring it outside the while loop, the same as you did $fg

You need to push $lin onto @arr

Unsure of what i'm talking about? You should read the basic datatypes, three, Arrays: A Tutorial/Reference, Lexical scoping like a fox

• Tutorials
• Getting Started with Perl
• Data Types and Variables
• the basic datatypes, three
• Data Type: Array
• Arrays: A Tutorial/Reference
• Getting Deeper Into Perl
• Variables and Scoping
• Variable Scoping in Perl: the basics
• Lexical scoping like a fox
  

FROM next i would take care of it.

Hi, its me again :)

I'm assuming this message was meant as a reply to Re^3: to copy certain content in file & repeat it .

Since PerlMonks offers threaded discussions, it is important to reply to the correct node by clicking the [reply] alongside the node of interest

This is something else to remember for next time

Thanks :)